DCIS is detected via breast screening programs, and frequency of diagnosis is on the increase.

Women older than 50 years who have been treated for ductal carcinoma in situ (DCIS) are more likely to still be living 10 years after treatment than women in the general population, according to study results presented at the 2017 European Cancer Congress.1

DCIS is noninvasive; however, it can progress into invasive breast cancer. Patients usually undergo surgery and might undergo radiotherapy. Because DCIS is detected via breast screening programs, frequency of diagnosis is increasing.

In this study, women treated for DCIS experienced a higher risk of dying from breast cancer but a slightly lower risk of all-cause mortality.

Researchers analyzed data on nearly 10,000 Dutch women with DCIS diagnosed between 1989 and 2004. Researchers tracked the patients' data for an average of 10 years, comparing death rates with expected mortality in the general population.

Women older than 50 years who had undergone treatment for DCIS experienced a 10% reduced risk of all-cause mortality compared with the general population.

A DCIS diagnosis can be distressing, and research has shown that many women overestimate their risks and are confused about treatment options. "This study should provide reassurance that a diagnosis of DCIS does not raise the risk of dying,” explained Lotte Elshof, MD, research physician and epidemiologist at the Netherlands Cancer Institute, Amsterdam, Netherlands.

"It might seem surprising that this group of women actually has a lower mortality rate than the general population. However, the vast majority would have been diagnosed via breast screening, which suggests they may be health-conscious and well enough to participate in screening."

Women with DCIS experienced a 2.5% risk of dying from breast cancer 10 years after treatment. This risk increased to 4% at 15 years. Although these rates are higher than in the general population, they are decreasing in women with more recently diagnosed DCIS.

Risk of all-cause mortality in women treated for DCIS was slightly lower due to decreased risks of dying from respiratory, circulatory, and digestive system diseases and from other cancers. These results suggest the potential side effects of radiotherapy do not significantly affect the health of nearby organs, such as the heart.